Fish ponds generally have gravel lining the bottom of the pond serving as a filter to catch excess debris, such as food and waste produced by the fish. Such debris, as well as decomposing plants, produce nitrogenous toxins which are harmful to fish and other living matter in the pond. Thus, regular maintenance of the pond includes removing the debris from the gravel. However, the accumulated debris hardens in the gravel, bonding individual stones together and thereby forming gravel clusters which makes removal of the debris difficult.
Gravel cleaners available for small aquariums comprise a suction device to lift the gravel from the aquarium bottom, separate it from debris, and return the gravel to the bottom. When gravel clusters enter a gravel cleaner for a small aquarium, the operator must tap the gravel cleaner against the aquarium wall to break up the cluster. In fish ponds, however, the gravel cleaners are large and such manipulation to break up the gravel cluster is not possible. Additionally, fish pond gravel clusters are larger than those in small aquariums and, consequently, more difficult to break up. Thus, prior art gravel cleaners are not designed to handle gravel clusters in large fish ponds.
Illustrative of prior art gravel cleaners for small aquariums are Dockery, U.S. Pat. No. 4,094,788; Sama, U.S. Pat. No. 4,290,883; Powers, U.S. Pat. No. 3,360,129; Willinger, U.S. Pat. No. 3,225,930; Leginus, U.S. Pat. No. 4,935,980; and Zweifel, U.S. Pat. No. 4,233,702. None of these are deemed to be suitable for cleaning the gravel in large-scale fish ponds.
Accordingly, there is a need for a gravel cleaner for use in ponds that will not only separate debris from gravel, but will also break up gravel clusters.